You don't want to use your stock fan. You want an nice after market cooler. The Hyper 212 EVO or Cryorig or H7 comes to mind.
Please note that overclocking is not a one click and done. It can take hours or days before you get the results you are looking for. It's all about trial and error. Download ASUS Realbench and run some test for hours at hand. Record the results. Then increase to see if you can go higher. If works, continue. If you crash, dial it back down. It's also about base clocks and vcore.
Here is a great guide: http://www.tomshardware.com/faq/id-2103175/bios-overclocking-beginners.html